Supplement: Power


How voltage supervisors address power supply noise and glitches


By Noel Tenorio, product applications engineer, Analog Devices U


sing voltage supervisors adds reliability to microcontroller- based systems by monitoring the power supply failures and putting the microcontroller


in reset mode to prevent system error and malfunction. However, power supply imperfections such as noise, voltage glitches, and transients can lead to false and nuisance resets that can affect the system behaviour. This article shows how voltage supervisors address factors that can trigger false and nuisance resets to improve the system’s performance and reliability.


Introduction


Applications that compute and process data requiring field programmable gate arrays (FPGAs), microprocessors, digital signal processors, and microcontrollers depend on safe and reliable operations. These devices tax power supply requirements as they are only allowed to operate at a certain range of power supply tolerance.1


Figure 1. The MAX705 supervisor is used to monitor a switching regulator output, which is the input voltage supply of a microcontroller.


Voltage supervisors are known solutions to achieve system reliability. They can act immediately to put the system in reset mode when an unexpected failure from the power supply arises, such as undervoltage or overvoltage. However, monitoring voltages in power supply rails always comes with some nuisances that can trigger unwanted false reset outputs. These are power supply noises, voltage transients, and glitches that can come from the power supply circuit itself. This article discusses the different parameters in a voltage supervisor that address unwanted power supply noises, voltage transients, and glitches. It also discusses how these parameters improve


30 December/January 2025 Components in Electronics


Figure 2. Voltage transients and glitches that can be observed on a supply voltage in different scenarios.


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